When a fusion reactor is finally operated successfully , no oil company or car company etc will be able to get in the way of the utilization of the suddenly massive amounts of energy available. Oil will be relegated to the role of lubrication and a source for hydrocarbons to produce plastics etc. Its role as a fuel will simply disappear in the country where fusion is harnessed.
That's my look into the crystal ball, I may be wrong.
There are so many possibilities that could arrise . Someone bmay find out that rollingb water over grren rabbit turds catalyzes the electrolysis to HHO with no other energy needed. Of course Green Rabbit Turds will go up in value if that happens.
I just think that since fusion appears to be the ultimate energy source in our solar system , it stands to reason that it will eventually be the ultimate energy source we harvest.